Ofgem said the retail profits of the Big Six have increased from £233 million to £1.1 billion in the past three years, with "no clear evidence" of companies becoming more efficient. It wants the new investigation to look into several key areas of concern:

Centrica announced today plans to build a new gas fired power station in England would be put on hold until the investigation is complete. Chief Executive Sam Laidlaw said:

Anything that clears the air and helps rebuild trust in the industry must be a good thing. Britain's energy market is highly competitive and we believe that a full independent review by a respected regulatory authority would demonstrate precisely that.

Whilst MoneySavingExpert.com founder Martin Lews welcomed the investigation, but said it was "very, very" overdue.